The present invention relates generally to a flushing device for water closets and more particularly to a water closet flushing device with a dual flush mechanism which uses a dual flush valve equipped with a height regulator.
Various dual flush mechanisms have been developed over the years for the purpose of providing the option of a full or long flush cycle for solid waste, or a short or partial flush cycle for liquid waste to save water during flushes that do not require the use of a full flush cycle. Conservation of natural resources such as water is important. Water closets which use less water to flush waste are most desirable.
Dual flush mechanisms have been constructed with two flush valves whereby each valve is operated by a separate knob or handle. The flush valves may be placed at different heights with respect to the bottom of the closet's tank. The actuation of the knob linked to the upper valve will produce a short or partial flush, while the actuation of the lower flush valve will produce a long or full flush. The length of the flush cycle is a function of the height of the flush valves with respect to the closet's bottom wall. The higher the valve is from the closet's bottom wall, the smaller the volume of water that will be discharged. Accordingly, the flushing of liquid waste, for example, requires the pressing of the upper flush valve operating knob since only a small amount of water is required for the flushing, while the flushing of solid waste requires the pressing of the knob linked to the lower flushing valve whereby a longer flush or a larger volume of flush water is produced. In this way, water conservation is ensured.
U.S. Pat. No. 5,333,332 to Kam, discloses a dual flush valve system in a closet using separate flush valve operating knobs. The system includes at least eight hinge points located between the lower and upper flush valve knobs and operating rods which effect a long or a short flush. Although there is a distinction between the short flush and long flush cycles, the dual flush system is very complicated, having many hinges operating the flush valve rod such that damage or failure of any of the hinges will effect failure of the overall function.
U.S. Pat. Nos. 2,839,759 and 2,864,095, both issued to the same inventor, Martino, disclose dual flush valves in which the base of the upper valve is controlled by means of a groove that regulates different heights of water in the closet tank. However, the structure of the valve rod operating hinges and the distance between the operating knobs are unable to ensure optimum performance. U.S. Pat. No. 3,795,016, discloses a water closet with dual flush valves which enable telescopic control, or lengthening or shortening, of the upper valve, which is strongly fixed by means of flanged bolts. In this invention, the arrangement of the flush valve operating hinges and the use of a single knob for operating the flush valve combine to give convenience to the user. However, the construction of the valve system is relatively complicated and the potential failure of the upper and lower flush valve operating hinges due to inadvertent excessive pressure on the knob can cause a large discharge of water.
Furthermore, U.S. Pat. No. 4,829,605 to Agustino, also discloses a dual flush valve having dual levers. One of the levers is for operating the half-volume flush valve and the other is for operating the full-volume flush valve. The two levers function as pressing knobs which are fixed in a non-parallel row. This invention does not give importance to the construction of the hinges of the lever or rod used for operating the individual valves. U.S. Pat. No. 4,011,604 to Goldswarthy relates to a dual flush system for closets with a lever operating construction that drives the flush valves separately. The weakness of the construction is in the length of the operating rod with respect to the handle or pressing knob. It is possible that the operating hinge which forms an "upside-down U" could lessen the operating capacity of the two flushing valves.
Accordingly, an improved dual flush mechanism that reduces unnecessary water consumption and which is of sound, simple construction is desired. It is preferable that the height of the mechanism be adjustable to accommodate the variation in tank size.